1. Field of the Invention
The present invention generally relates to image forming apparatuses, image formation enabling or disabling methods, and computer-readable storage media on which computer-readable programs are stored.
2. Description of the Related Art
An ink-jet image forming apparatus is provided with an ink cartridge that stores ink to be supplied to a recording head for forming images on a recording medium, such as paper, by jetting the ink. The ink cartridge may be detachably provided in the image forming apparatus, so that the ink may be supplied by replacing the ink cartridge.
If the recording is carried out until the ink remaining in the ink cartridge runs out, an erroneous recording or a deteriorated recording may occur. For this reason, the image forming apparatus may monitor the amount of ink remaining within the ink cartridge, and display a message urging a user to replace the ink cartridge when the remaining amount of ink approaches a certain amount. In addition, in order to prevent the erroneous or deteriorated recording, the image forming apparatus may restrict the recording when the remaining amount of ink approaches the certain amount.
However, when the ink runs out in the image forming apparatus described above, it may not be possible to carry out the recording if a new ink cartridge cannot be prepared to replace the ink cartridge that has run out of ink, or the recording needs to be carried out urgently.
Accordingly, a method has been proposed to provide in the image forming apparatus a first mode that restricts the recording when the remaining amount of ink approaches the certain amount and a second mode that does not restrict the recording regardless of the remaining amount of ink. The user may select the first mode or the second mode. An example of such a method is proposed in a Japanese Laid-Open Patent Publication No. 2004-174832.
However, according to the proposed method, the erroneous or deteriorated recording may occur before the recording is restricted in the first mode, depending on the amount of ink to be used to record the images in one job, for example.
On the other hand, the ink-jet image forming apparatus may include a sub tank that is connected to the recording head. The ink from the ink cartridge is supplied to the sub tank, and the sub tank supplies the ink to the recording head. In such an image forming apparatus, an amount of ink may remain within the sub tank even when the ink within the ink cartridge runs out. However, the erroneous or deteriorated recording may occur when the ink within the sub tank runs out before the ink cartridge is replaced, depending on the amount of ink to be used to record the images in one job, for example.